LONDON, Dec 6 (Reuters) - Most industrial metals prices fell on Thursday and copper hit a three-week low after the arrest of a top Chinese executive in Canada dampened hopes for a resolution to the U.S.-China trade conflict.

The arrest of tech giant Huawei's finance chief for extradition to the United States cast doubt over a 90-day trade truce struck on Saturday between the U.S. and Chinese presidents, Donald Trump and Xi Jinping.

It sent global stock markets sharply lower, and hit metals because investors fear tariffs will curtail China's demand for commodities.

Benchmark copper on the London Metal Exchange (LME) ended 1.7 percent down at $6,070 a tonne after touching its lowest since Nov. 14 at $6,068.

The Huawei arrest had combined with a plunge in oil prices to turn investors negative on metals, said Capital Economics analyst Ross Strachan.

"The optimism in the markets at the beginning of the week evaporated extremely quickly," he said.

Healthy supply-demand fundamentals, however, meant copper was unlikely to fall much further, he added, predicting a price of $6,250 a tonne at the end of 2019.

CHINA EXPORTS: China's economy is showing signs of cooling, with export growth expected to have slowed in November.

TRADE DISPUTE: Despite the Huawei arrest, China expressed confidence in striking a trade deal with the United States within their 90-day ceasefire period.

OIL: Oil fell more than 4 percent in choppy trading after OPEC and allied exporting countries ended a meeting without announcing a decision to cut crude output, and prepared to debate the matter the next day.

GERMAN EXPORTS: Strong foreign demand drove an unexpected rise in German industrial orders in October.

COPPER STOCKS: In a sign of tight supplies that should support prices, headline stocks of copper in LME-registered warehouses fell to 124,950 tonnes, down from almost 400,000 tonnes in March and the lowest since 2008. MCUSTX-TOTAL

SPREAD: The premium for cash copper over the three-month contract rose to $9.50 from zero on Wednesday, suggesting less availability of nearby metal, but it is still down from $44 in late November. MCU0-3

RUSAL: The top Democrat on the Senate Foreign Relations Committee urged the Trump administration not to waive or remove sanctions on Russian billionaire Oleg Deripaska or companies, including aluminium producer Rusal, that he controls.

OTHER METALS: LME aluminium closed 1.7 percent down at $1,936 a tonne, zinc ended down 1 percent at $2,593, nickel fell 3.3 percent to $10,850, tin finished 1.3 percent lower at $18,925 and lead eeked out a meagre gain of 0.1 percent to $1,984.

Additional reporting by Muyu Xu and Dominique Patton
Editing by David Goodman and Edmund Blair